Avocado Sustains a Complex of Neosilba spp. (Diptera: Lonchaeidae) in Veracruz, Mexico

Avocado (Persea americana Miller), a crop of major economic importance in Mexico, is threatened by several quarantine pests, and recent reports have suggested that the lance fly Neosilba batesi (Diptera: Lonchaeidae) may be responsible for significant yield losses. To clarify the role of this species, we surveyed avocados from six localities in Veracruz State on the Gulf coast of Mexico and identified lance flies using both morphological and molecular tools. None of the symptoms previously attributed to N. batesi infestation in Hass avocado were observed in any of the fruits inspected across the six localities. However, 90 fruits displayed clear signs of borer attack by Conotrachelus spp. or other primary pests, and 64 of these damaged fruits (60%) yielded lance flies. Hass avocados were rarely infested and hosted only N. batesi, whereas creole avocados (P. americana var. drymifolia) were hosts to N. batesi, N. glaberrima, N. recurva, and N. flavitarsis and an undescribed species (Neosilba sp.3) that was detected by analysis of the COI gene sequences of males. Additionally, Lonchaea cristula was reported for the first time emerging from creole avocado. Each avocado yielded an average of between 2.3 and 21.0 adult lance flies. Infestation was more frequent and numerous in fruits collected from the ground than in those harvested directly from trees, supporting the idea that lance flies preferentially exploit pre-damaged or fallen fruits. Indeed, lonchaeid eggs were frequently observed deposited on the periphery or inside oviposition holes created by other pests. Overall, our results indicate that Neosilba spp. act as secondary invaders in Veracruz, with no evidence of N. batesi behaving as a primary pest in this region. None of the avocados were infested by species of Tephritidae and none of the Neosilba species we identified appear to pose a threat to avocado production in Mexico. This study highlights the value of combining morphological and molecular tools for species identification and underscores the importance of differentiating between primary and secondary invaders in the context of avocado pest management.